A jewel wasp injects venom into a cockroach. The wasp can then manipulate the cockroach, turning it into a zombie, tugging on its antennae and leading it into a burrow, effectively controlling the cockroach against the insect’s will. Scientists hope that by studying the ways the venom effects the cockroach they can learn about Parkinson’s Disease in humans.

A rare wasp that uses its venom to control the mental activity of a cockroach — sending the bug into a zombie-like state — might hold the key to understanding what happens in the brains of people with Parkinson’s Disease, a recent study found.

A team of researchers, including undergraduate and graduate students at UC Riverside, studied the venom of jewel wasps, a creature that is native to the South Pacific. As part of its reproductive cycle, a jewel wasp will sting a cockroach, using its venom to turn the crawling scavenger into something akin to a zombie. The roach’s physical functions are frozen and controlled by the wasp, even though the roach remains alive for much of the wasp’s reproductive process.

The part of the study that looks specifically at how the cockroach brain responds to the wasp venom is expected to be published in the upcoming printissue of the journal Biochemistry and was published online Jan. 19.

“We can understand how the brain’s circuitry is altered to produce this reduction in movement,” said Michael E. Adams, a UC Riverside entomologist and neuroscientist who oversaw the study.

“We may have new ideas on how to reverse it.”

The bug’s reduced reactions to stimulation in some ways resembles the effects of Parkinson’s Disease, which is characterized by slower movement, rigid limbs and difficulty maintaining balance.

“(Parkinson’s) patients have trouble initiating movements and following through on movements,” Adams said.

“Once movements are initiated, they don’t function because of dopamine deficits” in the brain, he added.

Jewel wasps rely on cockroaches to host and feed their offspring. To breed, the wasp injects the roach with a special neurotoxin twice, once near the roach’s front legs and again directly into the roach’s brain. Within a matter of seconds the cockroach becomes less sensitive to stimulation and loses its ability to flee, though it remains alive.

“The animal is not paralyzed,” Adams said. “Its locomotive behavior is just altered. It doesn’t respond like it normally does to stimuli, (such as) air currents.”

The wasp then leads the cockroach into a burrow it has previously dug, implants the roach with a single egg, and seals off the seemingly hypnotized bug inside the burrow. Over the next week or so the wasp egg hatches inside the roach and feasts on the unsuspecting bug’s organs. After the roach dies, the young wasp emerges from the roach’s carcass.

The scientists at UC Riverside studied the wasp venom and found a molecule called “ampulexin,” which is unique to the jewel wasp and, the researchers believe, a possible key to the venom’s effect.

To suss out whether ampulexin is an active agent, the researchers injected two separate groups of roaches, some got natural wasp venom and others were shot up with a venom created only of ampulexin.

They then used electric stimulation to determine which roach group was most zombie-like. It turned out that roaches injected with natural jewel wasp venom were rendered more immobile, and for longer periods, than the roaches who were injected with ampulexin-only venom.

The effects of the natural venom, however, weren’t permanent. Within a week or so, the roaches — which weren’t being inhabited and consumed by wasp eggs — recovered.

“It’s reversible,” Adams said of the effects of the venom. “That’s another fascinating aspect of this.”

Scientists plan to study components in the venom other than the ampulexins. They also plan to study what happens inside the roach that, once injected with wasp venom, makes the roach lose control of its physical movements.

“Once we understand that, we may be able to wake (the roach) back up again,” Adams said.

A native of California, Lauren attended Cal State Long Beach where she majored in journalism and political science. She briefly lived in Santiago, Chile where she edited an online magazine and worked as a translator for doctors from Malaysia following Chile's 8.8 earthquake in 2010. Lauren moved back to the states in 2011 and now lives in Long Beach. A runner, rock climber and board game enthusiast, Lauren is perpetually training for the next race day.